International Journal of Cardiology 186 (2015) 149–151
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International Journal of Cardiology journal homepage: www.elsevier.com/locate/ijcard
Letter to the Editor
Cardiovascular disease is associated with the perception of worsening psychosocial work characteristics Jian Li a,⁎, Maureen F. Dollard b, Adrian Loerbroks a, Peter Angerer a a b
Institute of Occupational and Social Medicine, Centre for Health and Society, Faculty of Medicine, University of Düsseldorf, Universitätsstraße 1, 40225 Düsseldorf, Germany Asia Pacific Centre for Work Health and Safety, School of Psychology, Social Work and Social Policy, University of South Australia, Magill Campus, Adelaide, Australia
a r t i c l e
i n f o
Article history: Received 20 February 2015 Accepted 17 March 2015 Available online 18 March 2015 Keywords: Cardiovascular disease Psychosocial work characteristics Job strain Effort–reward imbalance Epidemiology
Much evidence has indicated that adverse psychosocial work characteristics (PWCs) in healthy employees increase the risk of subsequent cardiovascular disease (CVD) [1]. The models most widely used to measure PWCs are the job–demand–control (JDC) model and the effort–reward imbalance (ERI) model. The former model claims that stressful situations at work result from combination of high demand and low control; and the latter model emphasizes the failed reciprocity between effort spent and reward received [2]. Though the primary prevention of CVD is fundamental, its tertiary prevention (e.g. retaining job, and delaying disease progression) is of similar importance given that chronic diseases, particularly CVD, are becoming more prevalent in working populations [3]. A recent review suggests that chronically ill workers may experience worse quality of working life after return-to-work [3]. Yet, to our knowledge, no study has examined the impact of CVD on the perception of PWCs. We therefore aimed to address this knowledge. Data from two epidemiological studies were utilized. The first one was based on baseline data from the Australian Workplace Barometer (AWB) project, a nationally representative study on working conditions and health with 3826 employees being included in our data analyses. The second study was based on longitudinal data from the Chinese Nurses' Early eXiT (NEXT) study. 1791 female hospital nurses completed questionnaires at both baseline and a one-year follow-up, and 1486 free from any CVD were included in data analyses. Informed consent was obtained from each individual, and the studies adhere to the ⁎ Corresponding author. E-mail address:
[email protected] (J. Li).
http://dx.doi.org/10.1016/j.ijcard.2015.03.222 0167-5273/© 2015 Elsevier Ireland Ltd. All rights reserved.
Declaration of Helsinki. Details of the AWB project and the Chinese NEXT study were described elsewhere [4,5]. Four major PWCs, demand, control, effort, and reward, were measured in both studies, using validated short forms of JDC and ERI scales [6,7]. A ratio between demand and control was used to define job strain, and a ratio between effort and reward was calculated to quantify effort– reward imbalance. In order to harmonize the values across all PWCs, we presented the score ranges with 0–100, higher values reflecting higher demand, control, effort, and reward. In the Chinese study, all PWCs were measured at both baseline and follow-up, therefore the change scores (follow-up scores − baseline scores) were calculated. The prevalent CVD in the Australian employees and the incident CVD in the Chinese nurses were defined, according to self-reports, as suspected CVD (unconfirmed by physicians) and diagnosed CVD (confirmed by physicians) (Table 1). In statistical analyses, we treated prevalent CVD/incident CVD as independent variables, with the PWCs/changes in PWCs as dependent variables. Associations were estimated by multivariate linear models adjusting for relevant covariates (such as age, sex, marital status, and education). Results were presented as regression coefficients and 95% confidence intervals, indicating the differences of PWCs/changes in PWCs in the two groups of suspected and diagnosed CVD, compared to the group of no CVD (Table 2). The Australian employees were middle-aged, half were women, one third was single and one third was highly educated. They reported average levels of demand and effort, and relatively high levels of control and reward, resulting in lowered perception of stress at work (both demand–control ratio and effort–reward ratio b 1). Inspection of PWCs by CVD status suggested that all PWCs were rated worse in the two CVD groups versus those free of CVD. In the Chinese longitudinal sample, the female hospital nurses were young, half were married and half received higher education. At baseline and follow-up, they reported high levels of demand and effort, and average levels of control and reward, resulting in extremely high stress perception at work (both demand–control ratio and effort– reward ratio N1). It was found that, during the one-year observational period, in those who developed CVD, suspected or diagnosed, demand–control ratio had slightly increased (P b 0.05), while effort and effort–reward ratio had sharply increased, and reward had substantially decreased (P b 0.001). It has been hypothesized that functional impairments may conceivably hinder employees with chronic diseases from coping with their
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J. Li et al. / International Journal of Cardiology 186 (2015) 149–151
Table 1 Characteristics of study subjects. Continuous variables
Australian employees
Chinese nurses
N
Mean ± SD
N
Age at baseline (years) Demand at baseline (0–100) Control at baseline (0–100) Demand–control ratio at baseline Effort at baseline (0–100) Reward at baseline (0–100) Effort–reward ratio at baseline Demand at follow-up (0–100) Control at follow-up (0–100) Demand–control ratio at follow-up Effort at follow-up (0–100) Reward at follow-up (0–100) Effort–reward ratio at follow-up
3826 3826 3826 3826 3826 3826 3826 – – – – – –
45.34 ± 12.23 52.61 ± 17.05 61.86 ± 13.65 0.92 ± 0.23 53.72 ± 17.06 62.55 ± 15.13 0.94 ± 0.31 – – – – – –
1486 29.72 ± 7.43 1486 64.90 ± 15.43 1486 49.01 ± 16.34 1486 1.19 ± 0.27 1486 67.25 ± 18.11 1486 50.63 ± 13.16 1486 1.20 ± 0.31 1486 64.34 ± 13.98 1486 49.36 ± 15.39 1486 1.18 ± 0.25 1486 68.86 ± 16.44 1486 50.02 ± 11.37 1486 1.21 ± 0.28
Categorical variables
N
%
N
%
Gender at baseline: men Women Marital status at baseline: married Single Education at baseline: low High Prevalent CVD at baseline: no CVD Suspected CVD Diagnosed CVD Incident CVD at follow-up: no CVD Suspected CVD Diagnosed CVD
1770 2056 2622 1204 2524 1302 3283 378 165 – – –
46.26 53.74 68.53 31.47 65.97 34.03 85.81 9.88 4.31 – – –
– 1486 828 658 736 750 – – – 1297 156 33
– 100.00 55.72 44.28 49.53 50.47 – – – 87.28 10.50 2.22
Mean ± SD
In the Australian study, low education: lower than bachelor degree, high education: bachelor degree or above. In the Chinese study, low education: nursing school, high education: nursing college or above.
workload; and they have limited resources to influence work arrangement which causes reduced autonomy. In addition, they often experience less promotion opportunities and financial improvement (nonmaterial and material reward) after return-to-work [3]. Regarding CVD, we found that Australian employees with CVD would report worse PWCs in terms of the JDC and ERI models. Nevertheless, one needs to bear in mind that causal inference cannot be made from those cross-sectional results. Supplementarily, using longitudinal data from Chinese nurses, similar trends were observed, providing evidence of a potentially causal direction of CVD occurrence resulting in worsening PWCs, for the first time. If our findings are confirmed by future studies, policies regarding employees with CVD deserve more attention. In occupational settings, vocational rehabilitation during the past decades has focused on return-to-work for those with CVD, while less attention has been paid
to helping them stay at work. Some recent evidence indicated that an empowerment perspective is effective to job retention [8]. In clinical settings, a more comprehensive cardiac rehabilitation including a second phase, months after the return-to-work, may reduce psychosocial stress at work in CVD patients [9]. In return, working under psychosocial stress in employees with CVD was associated with a 65% excess risk to develop recurrent CVD events, according to a recent meta-analysis [10]. Two major limitations need to be addressed. First, the definition of CVD in our studies was broad including all types of categories from hypertension, angina, to myocardial infarction. The type of CVD and its severity should be considered in future research. Second, we utilized two datasets which were complementary due to non-overlapping strengths and weaknesses: the Australian study was cross-sectional, but had the advantage of being representative of the general working populations; by contrast, the Chinese longitudinal data in our analyses was restricted to one particular high-stress profession (i.e. nursing). Prospective research covering various occupations is needed. In conclusion, our findings suggest that cardiovascular disease worsens the perception of psychosocial work characteristics among the workers with CVD. Special attention should be paid in order to improve their psychosocial work environment and to prevent recurrent CVD events. Potential conflicts of interest The authors report no relationships that could be construed as a conflict of interest. Acknowledgments The Australian Workplace Barometer (AWB) project was supported by an Australian Research Council Discovery Grant (DP087900) awarded to Maureen F. Dollard and colleagues. The Chinese Nurses' Early eXiT (NEXT) study was supported by a Marie Curie International Incoming Fellowship within the 7th European Community Framework Programme (PIIF-GA-2008-220641) awarded to Jian Li. References [1] A. Fishta, E.M. Backé, Psychosocial stress at work and cardiovascular diseases: an overview of systematic reviews, Int. Arch. Occup. Environ. Health (Feb 17 2015)http://dx.doi.org/10.1007/s00420-015-1019-0 (Epub ahead of print). [2] L. Berkman, I. Kawachi, T. Theorell, Working conditions and health, in: L. Berkman, I. Kawachi, M. Glymour (Eds.), Social Epidemiology, Open University Press, New York, 2014, pp. 153–181. [3] M. de Jong, A.G. de Boer, S.J. Tamminga, M.H. Frings-Dresen, Quality of working life issues of employees with a chronic physical disease: a systematic review, J. Occup. Rehabil. 25 (2015) 182–196. [4] M.F. Dollard, T. Bailey, G. Hall, Surveillance system for psychosocial risk and testing the Australian Workplace Barometer theoretical model, in: M.F. Dollard, T.S. Bailey (Eds.), Australian Workplace Barometer: Psychosocial Safety Climate and Working
Table 2 Multivariate regression coefficients (95% confidence intervals) of psychosocial work characteristics by CVD. Australian employeesa
Demand at baseline
Control at baseline
Demand–control ratio at baseline
Effort at baseline
Reward at baseline
Effort–reward ratio at baseline
Prevalent CVD No CVD Suspected CVD Diagnosed CVD
0 3.82 (2.03, 5.62)⁎⁎⁎ 5.51 (2.85, 8.16)⁎⁎⁎
0 −0.88 (−2.24, 0.49) −2.24 (−4.26, −0.22)⁎
0 0.05 (0.02, 0.07)⁎⁎⁎ 0.09 (0.05, 0.12)⁎⁎⁎
0 2.70 (0.92, 4.48) ⁎⁎ 4.28 (1.65, 6.90)⁎⁎
0 −3.06 (−4.66, −1.45)⁎⁎⁎ −4.48 (−6.85, −2.11)⁎⁎⁎
0 0.07 (0.04, 0.10)⁎⁎⁎ 0.10 (0.06, 0.15)⁎⁎⁎
Chinese nurses b
Change in demand
Change in control
Change in demand–control ratio
Change in effort
Change in reward
Change in effort–reward ratio
Incident CVD No CVD Suspected CVD Diagnosed CVD
0 1.78 (−0.36, 3.93) 1.59 (−2.88, 6.07)
0 −1.12 (−3.39, 1.16) −3.50 (−8.24, 1.24)
0 0.04 (0.00, 0.08)⁎ 0.06 (−0.02, 0.14)
0 1.72 (−0.73, 4.16) 9.42 (4.33, 14.50)⁎⁎⁎
0 −3.52 (−5.23, −1.82)⁎⁎⁎ −2.43 (−5.99, 1.13)
0 0.08 (0.04, 0.12)⁎⁎⁎ 0.15 (0.06, 0.24)⁎⁎⁎
Linear regression, ⁎P b 0.05, ⁎⁎P b 0.01, ⁎⁎⁎P b 0.001. a Adjustment for age, sex, marital status, and education at baseline. b Adjustment for age, marital status, education, and psychosocial work characteristics at baseline.
J. Li et al. / International Journal of Cardiology 186 (2015) 149–151 Conditions in Australia, Australian Academic Press, Samford Valley QLD, 2014, pp. 25–51. [5] J. Li, H. Fu, Y. Hu, L. Shang, Y. Wu, T.S. Kristensen, et al., Psychosocial work environment and intention to leave the nursing profession: results from the longitudinal Chinese NEXT study, Scand. J. Public Health 38 (3 Suppl.) (2010) 69–80. [6] E.I. Fransson, S.T. Nyberg, K. Heikkilä, L. Alfredsson, D. de Bacquer, G.D. Batty, et al., Comparison of alternative versions of the job demand–control scales in 17 European cohort studies: the IPD-Work consortium, BMC Public Health 12 (2012 Jan 20) 62. [7] J. Siegrist, N. Dragano, S.T. Nyberg, T. Lunau, L. Alfredsson, R. Erbel, et al., Validating abbreviated measures of effort–reward imbalance at work in European cohort studies: the IPD-Work consortium, Int. Arch. Occup. Environ. Health 87 (2014) 249–256.
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